1. Field of the Invention
This invention relates to means for accurately registering a first member an interdependent relationship to a second member and more particularly to apparatus for accurately registering a reference member in a co-acting interdependent relationship to one or more of a plurality of moveable members. The apparatus disclosed herein utilizes a three-point registration system utilizing a cone, vee groove and flat planar surface which cooperate with alignment pins having spherical shape ends to form a highly accurate mechanical registration means. This invention has particular utility in a vacuum thin film vapor deposition system for accurately registering a substrate to a series of deposition masks in a vapor deposition process.
2. Description of the Prior Art
The use of alignment pins and alignment pin receiving means are well known in the art as a means for registering a first member to a second member. Specifically, the use of a three-element pin and aperture alignment system for aligning a first member to a second member is disclosed in U.S. Pat. Nos. 3,694,919 and 3,510,947.
The apparatus disclosed in U.S. Pat. No. 3,694,919 is a dental articulator which utilizes a pair of simulated socket members and a rest pin as a means to register an upper assembly to a lower assembly. The simulated socket members each include a spherical stylus and a simulated socket which cooperates with the stylus to provide two pivot points which are adapted to provide a common axis about which a frame can be rotated. The rest pin is adapted to come into contact with a rest block on the lower assembly which provides a third point of support. The upper assembly is removable from the lower assembly by separating the rest pin from the block and the upper assembly from the two spherical shaped stylus members such that the simulated socket members can be removed from contact therewith which makes the upper assembly easily separable from the lower assembly which supports the two spherical shaped stylus members and the rest block. The upper assembly can be positioned back into registration with the lower assembly by placing the simulated socket members back onto the spherical shaped stylus members and then rotating the upper assembly relative to the common axis defined by the line of rotation extending between the centers of the spherical shaped stylus members until the rest pin on the upper assembly engages the rest block.
Another known three-element registration system for registering a first member in operative relationship to a second member is disclosed in U.S. Pat. No. 3,510,947 which is in the form of an interchangeable dental articulator. Stud members having alignment pins are cast into a base member in a predetermined pattern such that the alignment pins extend outwardly from the upper surface of the base member. The stud members comprise a collar of substantially cylindrical configuration having the alignment pins in the form of a cone shaped member defining an inverted frusto conical member extending coaxially therefrom positioned on one side and a similar shaped element extending from the other side thereof and into the base member. The second member, which may be a dental model, has three alignment pin and collar receiving holes formed in the bottom thereof in substantially the same pattern as the alignment pins positioned in the base member. An elastic or resilient, annular shaped member having an aperture extending through the center thereof is cast into the material forming the second member. The dental model can be positioned in operative relationship to the base member by positioning the apertures containing the annular shaped member over the alignment pin extending from the upper surface of the base member and the dental model can be removably affixed to the base member by urging the dental model into engagement with the base member driving the alignment pin into engagement with and deforming the annular shaped member so that the collar can pass therethrough to maintain the dental model in position relative to the base. The dental model can be removed from the base by applying sufficient separation force between the dental model and the base to cause distortion of the annular member and to pull the column member through and further deforming the annular shaped member to permit separation thereof.
The use of a three-element apparatus for registering an optical diffraction grating member to a support for accurate mechanical registration as required is utilized in a scanning monochrometer known as the ARL-FICA Quantoscan which is offered for sale and sold by Applied Research Laboratories. The Quantoscan scanning monochrometer utilizes a diffraction grating which must be positioned in a vertical plane and located very accurately relative to two reflective members and two slits to provide a precise defraction pattern relative to a light source and detector. In using the Quantoscan scanning monochrometer, it is sometimes necessary to remove the grating member in order to clean the same or to otherwise maintain the apparatus. It is essential that the grating member be accurately positioned back onto its support so that repeatable readings can be obtained in a monochrometer. In order to obtain the accurate registration of the grating to the support, a three-element registration system is utilized which is formed of three ball elements which cooperate with a cone, vee groove and flat. The grating member contained alignment balls are adapted to cooperate with the cone, vee groove and flat which is located on the grating support. A spring support was connected between the grating member and a support to provide a positive clamping force onto the grating to urge the alignment balls into intimate engagement with the cone, vee groove and flat supports and to counteract the gravitational force acting on the vertically supported grating. Accurate alignment between the grating and other optical members was obtained by adjustment of the grating support carrying the cone, vee groove and planar member relative to the frame supporting the other optical members. Once the appropriate adjustment was obtained, the grating member could be removed by releasing the clamping force therefrom and could be cleaned or otherwise maintained. The grating member was capable of being reinstalled in a reproducible registration to the base by positioning the balls back into engagement with the cone, vee groove and flat surface and reattaching the spring member thereto.
Each of the above described prior art devices perform the function of engagement and registration of a first member with a second member in ambient atmosphere.
The use of a two-point support system for a magnetic head in a magnetic disk recording system is disclosed in U.S. Pat. No. 3,774,183. The two-point support system permits the head to exhibit movement in the form of pitch and roll only, while prohibiting yaw, as the head flies over the surface of a magnetic recording disk.
In the two-point support system, a pivot bar attached to a transducer has two apertures, one of which is generally circular in crossectional shape having inwardly sloping sidewalls to define a conical shaped surface and the other aperture which is generally elliptical in cross-sectional shape having inwardly sloping walls forming a conical shaped surface. Two pin members attached to compliant springs, each having a spherical end which is positioned one each in each one of the apertures, enables the transducer to roll and pivot but restricts lateral movement and yaw of the transducer.
It is also known in the art to utilize apparatus for registering a deposition mask to a substrate for producing thin film magnetic transducers using a vapor deposition process. One such technique is disclosed in U.S. Pat. No. 3,867,868 to Lazzari.
In fabrication of a thin film transducer having pole piece layers and one or more winding layers and insulation layers, any one of several techniques can be used in an attempt to precisely control the width, depth and registration of the various layers relative to the prior deposited and post deposited layers. The Lazzari apparatus utilized in fabricating such thin film transducers relies on the use of a rolling mask-carriage assembly positioned by a lead screw which functionally attempted to index and accurately position a specific deposition mask pattern relative to a substrate held by a pivoting arm.
In known vapor deposition processes, the use of pins, dowels or extending members in cooperation with apertures, which may either be cylindrical or elliptical in shaped, result in a high degree of friction being developed between the dowel pins and the receiving apertures which cooperate with the dowel pins. The high degree of friction is due to the fact that lubricants and surface contaminates are removed from the dowel pins and the inner walls defining the aperture. The contaminates include adsorbed gasses, lubricating contaminates, and the like which are removed from the surfaces of the engaging elements located in the chamber of the vacuum deposition apparatus by the pumping of the vacuum and the use of high temperatures typical of deposition processes.
In such alignment devices, clearance must be provided in order to permit engagement and disengagement of the apertures and cooperating alignment dowels or pins on members to be aligned. The amount of clearance directly affects the accuracy of registration of the registered members. Also, binding or siezing of the members can be experienced during engagement or disengagement of the apertures and cooperating alignment dowels or pins due to tilting or other angular misalignment between the members and due to discrepancies in center line distance between various interacting elements.
In a vacuum deposition process, it is known in the art that the coefficient of friction, both dynamic coefficient of friction and static coefficient of friction, are extremely high compared to ambient atmosphere conditions. This is due primarily to the high degree of atomic adhesion or binding which occurs between the surface of the components due to removal of a substantial portion of adsorbed gasses and surface contamination.